1. Field of the Invention
The present invention relates to a door lock drive unit. More particularly, the present invention relates to a door lock drive unit in which an unlatch mechanism for releasing a door lock engagement mechanism and a closing mechanism for closing a latch from a half latch state to a full latch state are composed of one motor.
2. Description of the Related Art
Conventionally, there is provided a door lock drive unit for vehicle use in which one motor conducts an unlatch function to unlatch a latch from a door closing state to an unlatch state by rotating the motor normally and also conducts a closing function to close the latch from an incomplete door closing state (half latch state) to a door closing state (full latch state) by reversing the motor.
The door lock drive unit must have a large-ratio reduction gear which is housed in an actuator and conducts a closing function using a drive force generated by a motor because it is necessary to provide a large torque in the case of a closing operation and also it is necessary to conduct the closing operation slowly. In this connection, the reason why it is necessary to conduct the closing operation slowly is described below. If the closing operation is conducted quickly, the following problems may be encountered. When it is necessary to stop a closing motion of a door in the case of emergency in which a finger is pinched by the door, it takes time to stop the closing motion and even if a sensor, to detect a finger, is provided, a time lag necessarily occurs from the time of detection by the sensor to the time of stopping of a motor. When a large-ratio reduction gear is incorporated into the actuator of the prior art, the size of the door lock drive unit is increased.
In the case of emergency in which a finger is pinched by the door in the middle of closing operation (in the process from a door open state to a door closed state), it is required that the closing operation is stopped and the stopping position of the closing operation is changed over to the unlatch operation (door opening motion) even in the middle of closing operation.
In view of the above problems, it is an object of the present invention to provide a door lock drive unit capable of conducting both the unlatch function and the closing function using one motor, characterized in that: the size of the door lock drive unit can be reduced; and safety can be ensured in the case of emergency in which a finger is pinched.
In order to solve the above problems, the door lock drive unit of the present invention operates as follows. Rotation of an output shaft of one motor, which is normally rotated and reversed, is reduced by a reduction gear and rotates an engagement member and an output cam. When the motor normally rotates the engagement member and the rotation is transmitted to the first output shaft, the first output shaft activates the door lock and conducts unlatch operation (unlatch function). Also, when the motor reverses, the output cam and the rotation is transmitted to the second output shaft, the second output shaft activates the door lock and conducts a closing operation (closing function).
As described above, a unlatch mechanism and a closing mechanism, in which unlatch operation and closing operation are separately conducted by the normal and the reverse rotation of the gear unit, are provided. Even in the middle of a closing operation conducted by the reverse rotation of the gear unit, the closing operation is stopped (The motor is stopped.), and then, when the motor is normally rotated, it is possible to change over from the stopping position of the closing operation to the unlatch operation (door opening operation). Due to the foregoing, it is possible to reduce the size of a door lock drive unit capable of conducting both the unlatch function and the closing function by one motor and, further, safety can be ensured in the case of an emergency in which a finger is pinched.
The present invention may be more fully understood from the description of preferred embodiments of the invention, as set forth below, together with the accompanying drawings.